core 5 - p3 Flashcards
(25 cards)
State Boyle’s Law and write its formula.
“For a fixed mass of gas at constant temperature, pressure is inversely proportional to volume.”
Formula: P1 V1= P2 V2
Convert polar coordinates
(8,45 ∘ ) to Cartesian coordinates.
x=8cos45 ∘ = 5.66,
y=8sin45 ∘ = 5.66.
Result: (5.66,5.66).
What is Young’s modulus, and how is it calculated?
A measure of material stiffness. Formula:
E = stress / strain = (F/A) / (ΔL/L)
A gas at 2 atm occupies 4 L. Calculate its volume at 4 atm (constant temperature).
Using Boyle’s Law:
2 × 4 = 4 × V2 → V2 = 2 L.
Define specific latent heat of vaporization.
The energy required to convert 1 kg of a liquid to gas at its boiling point without temperature change.
What is the characteristic gas equation?
pV = mRT, where R is the specific gas constant, T is temperature (K), and m is mass.
A simply supported beam of length 6 m has a 300 N load at its midpoint. Calculate the reaction forces.
Symmetric load → R1= R2 = 300 / 2 = 150N
What is the difference between scalar and vector quantities?
Scalars have magnitude only (e.g., mass), while vectors have magnitude and direction (e.g., velocity).
Convert 50 inches to meters (1 inch = 0.0254 m).
50×0.0254=1.27m.
Explain thermal conductivity and its units.
A material’s ability to conduct heat. Units: (watts per meter-kelvin).
What is shear force in a beam?
The internal force perpendicular to the beam’s longitudinal axis, causing sliding deformation.
Calculate the moment of inertia for a 2 kg mass 3 m from the axis.
Using the formula for a point mass:
I = mr ^ 2 = 2 kg × (3m) ^ 2 = 2 × 9 =18
Define absolute pressure and how it differs from gauge pressure.
Absolute pressure = Gauge pressure + Atmospheric pressure. It is measured relative to a vacuum.
What is a cantilever beam?
A beam fixed at one end and free at the other, e.g., a diving board.
A hydraulic system has a piston area of
0.02 m ². If the pressure is
500kPa, calculate the force.
F = PA = 500,000 × 0.02 = 10,000N.
What are the four steps of the scientific method?
-Observation
-Hypothesis
-Experimentation
-Conclusion
Convert 150°C to Kelvin.
T(K)=150+273.15=423.15K.
Define uniformly distributed load (UDL).
A load spread evenly over a beam’s length (e.g., the beam’s own weight).
What is Poisson’s ratio?
The ratio of transverse strain to axial strain: ν = − ϵtransverse/ ϵaxial.
A 10 m steel rod (α=12×10 ^ −6 K ^ −1) heats from 20°C to 120°C. Calculate expansion
ΔL=10×12×10 ^ −6 ×100=0.012m.
What is the principle of moments?
For equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments.
Explain Hooke’s Law and its limit.
“Stress is proportional to strain within the elastic limit.” Beyond this, deformation becomes plastic.
Calculate stress if a 1000 N force acts on a 0.1m² area.
Stress = F / A= 1000 / 0.1=10,000Pa.
What is a colloid, and give an example.
A mixture with particles larger than solutions but smaller than suspensions (e.g., milk, fog).
